Process of making fused bifocal lenses



Feb, '12 mm. msww L; W. BUGBEE PROCESS MAKING FUSED BIFOCAL LENSES Fil ed May 5, 1921 T lia. 2 3

/ a I I Patented Feb. 12, was.

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LUCIAN W. BUGBEE, F INDIANAPOLIS, INDIANA, ASSIGNOR T0 FRANKLIN OPTICAL COMPANY, OF INDIANAPOLIS, INDIANA, A CGEPORATION 0F ENDIANA.

PROCESS OF MAKING FUSED BIFOCAL LENSES.

Application filed may 5,

To all whom it may concern:

Be it, knownthat I, LUCIAN W. Became, a citizen of the United States, and a resident of Indianapolis, county of Marion and State a of Indiana,'have invented a certain new and useful. Process of Making Fused Bifocal Lenses; and I do hereby declare that the following is a full, clear, and exact description thereof, reference beinghad to the acl0 companying drawings in which like numerals refer to like parts.

Thecbject of this invention is to make a fused bifocal or Kryptok lens or blank in which the reading segment varies in charl acter from its center to its circumference.

to the eye of the user of the lens, or with.

the colors of the various portions of the lens graduated so as to make the lens look well and be easy to the eye of the user.

80 The full nature of the invention will be understood from the accompanying drawings and the following description and claims:

In the drawings, F ig.- 1 is a plan view of a fused bifocal blank with the outline of the finished lens indicated by a dotted line.

Fig. 2 is a plan view of such a blank with the flint glass insert in the recess of the main portion of the lens shown in its posi- 'tion and condition when first placed in said I recess. Fig. 3 is the same after the partitions have been removed from-the recess.

Fig.4 is a central section of Fig. 2. Fig.

5 is a central section of Fig. 3. Fig. (5 is the same as Fig. 3 after fusing. F lg. 7

shows a lens after it is ground and polished.

The process consists in providing the usual crown glass main portion 10 of a lens of this type'with a recess 11 made in any so desired Way, but preferably with a wall or shoulder 12 at the margin of said recess.

Then there is placed in said recess a pluralit of annular or ring-like partition ban s 13 and 14fconcentric to said recess As here shown there are two of said rings 1921. Serial No. 467,141.

used which divide thespace in said recess into three concentric zones and of substantially the same width.

Then different varieties or qualities of flint glass or glass of a higher index of refraction than the main portion of the lens are made or obtained. The selection of this flint glass should vary gradually in index of refraction from a relatively low index to as high an index as desired. The different qualitiesof flint glass are separately broken into small partiolesand each quantity of particles is separately formed in the nodules, preferably ,by revolving them in a container in which they grind the sharp in edges away and leave rounded nodules. Then the dust and small irregular particles are sifted out tibm among the nodules.

The nodules of the flint glass having the highest index of refraction are placed in the center band or ring and those of the glass having the next lower index of refraction are placed in the middle band or ring, and those of a still lower index are placed in the recess surrounding the outer 50 ring or band. This forms three zones instead of two and the nodules are heaped up to a level higher than the main body of the lens, as shown in Fig; 4.

The next step in the process is to remove the rings or bands, which, by the way, are made of metal or any suitable material, and that leaves a mass of nodules substantially as shown in Figs. 3 and 5. The same then is subjected to sufiicientheat to fuse the nodules of flint glass together and fill the recess and secure the same to the crown glass portion of the lens, as shown in Fig. 6. After that the lens is ground and polished, as shown in Fig. 7. While piano lens blanks are shown in the drawings, the invention is not limited to any particular form of lens.

The invention cla med is:

1. In the process of making fused bifocal lenses. placing upon the main portion of the 100 lens glass particles arranged in concentric zones differing in their indices of refraction, and then fusing the same to the main portion of the lens. 7

*2. The process of making fused bifocal ion lenses, which process consists in forming the main portion of the lens with a recess 'for the reading seg'ine'nt, placing in saidrecess concentric zonesmt nodules of glass having diflerent indices of refraction, sub- 2.30

nodules of portion of the lens, and grinding and polishing the same.

jecting the same to heat for fusing the glass together and to the main 3. The process of making fu sedbifocel lenses, which process consiststo receive the reading segment, placing'in said recess concentric partition hands, lea-vmg annular chambers in and surrounding said bands. filling said chambers, with -the main portion of the lens with a recess to receive a reading segment, placing in said reading segment concentric partition hands which leave chambers in and. around said bands. filling said chambers with nodules of glass of a higher index of refraction-than the main portion of the lens and with the indices 'of said groups of nodules diminishing from in forming. the main portion of the lens with a r'ecess :neeeasoe the center tothe main portion of the. lens, removing said partition bands, fusing said glass nodules together into the main o'rtion of the lens, and-grinding and polishin the lens. t I

5. The process of making fused bifocal lenses, whichYprocess consists in forming the main portion of the lens with a recess to receive the reading segment, placing in said recess concentric partition bands, leaving chambers in and'around said bands, crushing; different bodies of. glass having a higher index of refraction than the main portion ofthe lens into particles, treating said particles to round them into nodules, placing in each of said chambers nodules of a single index 'and'with the indices of the series of chambers diminishingfrom the center to the main portionof the lens, re-

moving said partition bands, fusingsaid nodules together and to the main portion of the lens, and grindin; and polishing the same."-

.In witness whercofiI havehereunt'o afiixed vmy signature.

LUGI'AN W. humane. 

